The broad objective of the proposed research is to investigate functional impairment and adaptation in adults with disrupted written sentence comprehension subsequent to brain damage. The focus of the research is to identify impairments of specific sentence processing operations that result in an inability to assign and/or interpret syntactic structure. The specific aims are, 1) to characterize impairments in written sentence comprehension within a linguistic framework and to use widely accepted notions of parsing to propose an underlying processing deficit; 2) to verify the characterization of the deficit by testing whether it generalizes to related sentence structures as defined by the linguistic framework: 3) to verify the proposed processing deficit by testing whether it generalizes to other sentence processing tasks; 4) to investigate the compensatory mechanisms that aphasic patients utilize as an adaptation to the deficit. The methodology involves the testing of multiple syntactic structures in multiple tasks. To achieve the first two specific aims, an individual aphasic subject's deficit will be characterized in linguistic terms and verified through the use of sentence structures varying in syntactic and propositional complexity with an object manipulation task. To meet the third specific aim, the locus of the processing deficit will be verified through the use of a grammaticality-judgment task and a self-paced reading task. The fourth specific aim will be achieved by examining the subject's systematic response patterns throughout the tasks. The proposed study will enrich understanding of specific sentence processing operations and their breakdown in pathology through its attention to a precise characterization of impaired performance in formal linguistic and processing terms and verification across task variations. In addition, the proposed study will provide insights into the nature of compensatory strategies used by aphasic subjects as an adaptation to the deficit.